Circuit interrupter



. Oct. '20, 1.942,.

J. M. WALLACE CIRCUIT INTERRUPTER Filed Dec. 28, 1939 WITNESSES: W

mim

2 Sheets-Sheet l 6'3 Fly 2 INVENTOR James 2% Wallace.

Oct. 20, 1942. J WALLACE 2,299,196

CIRCUIT INTERRUPTER Filed Dec. 28, 1939 2 Sheets-Sheet 2 WITNESSES: INVENTOR 4* James M Wallace.

(RILQWT M 92k Patented Oct. 20, 1942 CIRCUIT INTERRUPTER James M. Wallace, Braddock, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh-Pa a corporation of Pennsylvania 7 Application December 28, 1939, Serial No. 311,357

28 Claims.

My invention rotates, in general, to circuit 'interrupters, and more particularly to interrupters which are adapted to automatically drop out, or remove themselves from a circuit follow ing ,actuation thereof to interrupt the circuit.

The interrupter constituting my invention preferably is of the type which operates to automatically interrupt a circuit in response to the passage therethrough of currents above a predetermined value, such as overload and short circuit currents, and will be disclosed as a high voltage fuse of the so-called drop-out type.

It is an object of my invention to provide an interrupter with novel means for removing the same from an electric circuit following an interrupting operation.

A'furtherobject of my invention is to provide a high voltage fuse with novel and efficient means for enabling it to drop out of its associated circuit in response to blowing of the fuse.

A further object of my invention is to provide an interrupter of the type described, constructed, and arranged so as to be substantially closed to the surrounding atmosphere, excepting at one end thereof upon the occurrence of an interrupting operation.

Another object of my invention is to provide an interrupter of the type described which is normally locked in an electric circuit, with novel means for positively releasing said locking means in response to an interrupting operation A further object of my invention is to provide a spring biaszd high voltage fuse with novel means controlled by the spring upon blowing of the fuse for operating latch release means on the fuse.

These and other objects of my invention will become more apparent upon consideration of the following specification of preferred embodiments thereof, taken in connection with the attached drawings, in which:

Figure l is a side elevational view of a high voltage fuse embodying my invention and mounted in a normal operating position;

Fig. 2 is a longitudinal cross-sectional view of 4 the fuse shown in Fig. 1 and showing a portion of the latch for the fuse;

Fig. 3 is a longitudinal cross-sectional view of the upper end of the fuse shown in Fig. 2 and showing a portion of the latch. means in disen aged position.

shown in Fig. 1 with the fuse shown in an open or drop-out position; and

Fig. 6 is a longitudinal cross-sectional view through the upper portion of a fuse and latch thereof with a slightly modified form of latch releasing means.

Referring to the drawings, I have shown in Fig. 1 a channel supporting member 2 to which are secured the spaced insulator supports 4 and 6. The lower insulating support 6 is provided with an outer terminal cap 8 which includes a ter minal connector 9, and outwardly extending spaced arms between which a fuse is adapted to be received. Each arm is provided with a lower forwardly and upwardly extending hook portion ID for guiding a fuse pivot pin i2 into a notch provided in the arm for pivotallysupporting the lower end of the fuse IS. The pivot pin l2 of the fuse I6 is secured on a lower terminal ferrule 18 of the fuse, which is also provided with a stop pin i l for limiting pivotal movement of the fuse in a clockwise direction. The upper in sulator 4 is also provided with a terminal cap including a terminal connector portion 19, and spaced forwardly extending resilient contact arms 21!, for receiving the upper fuse terminal cap 22 therebetween. The upper insulator cap is also provided with forwardly extending spaced latch supporting arms 24 for receiving therebetween spaced leg portions 38 of a latch 28 which.

leg portions are pivotallymounted on the pivot pin 32 provided in the supporting legs 24. A spring 34 is coiled about the pivot pin 32 between the latch legs 30, and has one end thereof bearing against the insulator terminal cap, and the other end thereof bearing against the latch 28 as shown-in Fig. 4. The latch supporting arms 24 on the upper insulator terminal cap are pro- Fig. 4 is a top vicw of the structure shown in Fig, 5 is a fragmentary elevational view of the lower support and the lower end of the fuse vided with an integral connecting stop bar 26 which lies beneath the latch 28 to limit downward movement of the latch in a clockwise direction about the pivot 32 to substantially the position shown in Fig. 2. The coil spring 34 will normally urge the latch downwardly against the stop bar 26. The underside of the latch 28 is provided with a notch 35 to receive a projection provided on a cap nut 38 on theupper fuse terminal cap 22.

Obviously. in the position shown in Figs. 1 and 2 the fuse is locked by the latch 28 in the position shown in engagement with the upper contact arms 20, which are constructed so as to be resilient and in a stressed condition when the fuse is locked. in the position shown. If the latch 28 is moved upwardly or in a counterclockwise direction about its pivot 32; sufficient to release the projection on the cap nut 38, the stressed contact 'arms 20 will then force the fuse tube outwardly or in a clockwise direction about its pivot pins l2, to a position such as that shown in Fig. 5 where the stoppins It engage the outer ends of the hooks l0 provided on the lower insulator cap 8. In this position of the fuse a relatively large air gap will be inserted between the upper fuse terminal cap and the upper contacts 20.. v v

The fuse l6, as shown in Fig. 2, includes an outer insulating tube 40' which may be of any desired insulating material such, for example, as porcelain, glass, fiber, or the like, having the upper fuse cap 22 threadedly mounted on the upper end thereof, and the fuse ferrule l8 threadedly engaged with the lower end thereof. In the lower end of the fuse tube 80 there is provided a fuse refill unit which includes an insulating tube 32 of fiber or the like, having a conducting ferrule terminal portion 46 threaded on the lower end thereof. The ferrule M is rigidly secured the fuse tube and terminating in spaced arms,

providing a slot 64 therebetween at the outer end of the extension 62. Pivotally mounted in the slot 64 as by the pivot pin 61, is a latch release lever 66 in the form of a bell crank lever, one arm 68 of which extends in an inclined direction uption I2 for the reception of a hook stick or other operating means. In the upper end of the fuse tube I have provided an inner actuating tube 13 between the spring 60 and the inner .wall of the with respect to the terminal ferrule I8 by the clamping. ring 46, threaded into the outer end of the terminal ferrule iii. The refill insulating tube 42 is provided with a lining of a material 48 which is capable of evolving an arc-extin- 1 guishing gas when in proximity to an electric arc such, for example, as boric acid, a synthetic resin, or fiber. provided with a central bore in which is located an arc-,drawing rod 50, the lower end of which is secured to the refill terminal ferrule '44 by a fusible connection 52 and a strain element 5h The upper end of the arc-drawing rod 50 is secation. Inasmuch as this patent shows in detail The gas-evolving material is.

outer insulating tube 40. This actuating tube 13 is freely slidably mounted within the outer insulating tube 48. and is provided adjacent its upper end with an aperture 15 for receiving the free end of the lower arm 10, of the latch release member 66. V

In the operation of the latch releasing means, when the fuse blows as previously describedthe spring 60 withdraws the arc-drawing rod 50 and moves it and the plunger 56 upwardly, as seen in Figs. 2 and 3, until the plunger engages the lowerend of the actuating tube 13. movement of the plunger 56 under the influence of spring 60 results in movement of the actuating tube-=13 upwardly to the position shown in Fig. '3-

the fuse tube from the latch, and permits the. fuse IS in move outwardly to the position shown in Fig. 5; as described above. Following blowing of the fuse and .its movement to the position shown in Fig. 5, the fuse may be refilled and then manually reinserted in the circuit by insertinga hook stick in the aperture of ring 12 and moving the outerend of the fuse IS in a counterclockwise. direction from the position shown the construction of the fuserefill and 'its connection to an upper terminal cap, including the connections of the coil spring 60 to the refill and to the upper terminal cap, and the manner in which these parts may be renewed after the fuse blows, reference is made to this patent for a detailed description of these parts and connections.

In general, the operation of a fuse of this type' is as folldws: Upon the passage of predetermined overload currents through the fuse, the fusible connection 52 melts as does the strain'element -;54, whereupon the spring 60 is free to draw the in Fig. 5 to the position shown in Fig. 1. In moving to this position, the projection on the cap nut 38at the top of the fuse will engage the outer curved end of the latch 28 to move the latch upwardly against the bias of spring 34, until the projection on the cap nut 38 comes 'into alignment with the notch 36 provided on the lower side of the latch, whereupon the latch will automatically operate to lock the fuse in its normal position shown in Fig. 1. From the foregoing, it is obvious that when the fuse blows the latch 28 which normally locks the fuse in engagement with circuit contacts is automatically released so that the resilient contact arms 20 may operate evolving material l8 which will evolve quantities to move the fuse out ofgengagement with its circuit contacts to a drop-out position such as that shown in Fig. 5.

' The fuse l6 may also be manually disconnected from its associated circuitby inserting a hook stick or other operating member in the aperture through ring 12 of latch release member 66, and pulling downwardly and outwardly to rotate the latch release member 66 in a clockwise direction about its pivotSl, which will raise the latch 28 out of engagement with the projection on the cap screw 38'on theupper end of the fuse, and permit rotation of the fuse IE to the position shown in Fig. 5, or permit its complete removal from both the upper and lower line contact.

,With the foregoing fuse and latch release con- Further ward movement of the actuating rod 88.

struction it should be noted that a positive actuation of the release means is obtained by virtue of the fact that the plunger 56, in moving upwardly, engages the latch release actuating sleeve 13 before the plunger 56 reaches the end of its path of movement under the influence of the coil tension spring 68. In other words, the latch release actuating sleeve 13 is positively moved upwardly by the coil spring 68 and is retained in this upper position inasmuch as the stress on coil spring 68 is not entirely relieved even when the parts have attained the position shown in Fig. 3. It should also be noted that at the time the plunger. 56 engages the latch release actuating sleeve 13, the arc-drawing rod 58 is substantially at the upper end of the herein the gas-evolving material 48 but is not as yet withdrawn therefrom. This insures that the arc will be extended to the maximum length of the gas-evolving material 48, before the latch'28 is released to permit the fuse l6 to be disengaged from the .contact arms 28. Therefore, the arc will have been extinguished I before the upper fuse terminal ferrule 22 moves awayfrom the contact arms 28 so that no arc will be drawn at this point.

In Fig. 6 I have shown a fuse substantially like that described in connection with Figs. 1 to 5 but having a slightly modified latch release conaperture 18 in which is longitudinally slidably received an actuating rod 88. The actuating rod 88 terminates in an inner head portion 88 normally spring urged inwardly by a coil compression spring 98 engaging between the head 88- and the outer end of the bore 16. A release'tube 92 which is freely movable longitudinally within the outer fuse tube 48 is provided between the fuse'tube48 and the coil spring 68. The release tube'92 is provided at its upper end with an enlarged head portion 94 which is stepped to provide shoulders 96 and 98. As shown in Fig. 6, the head 88 of the actuating rod 88 is normally engaged beneath the shoulder 96 on the tube 92, thus limiting the in- The extension 14 on the upper terminal cap 22 is provided at itsupper outer end with a pair of spaced outwardly extending supporting arms 85,

between which is pivotally supported as by a pivot pin 83, a latch releasing lever 82. As shown in full lines in Fig. 6 the latch releasing lever 82 has one end portion 81 extending into substantial engagement with the latch 28, and another portion on the" opposite side of pivot 83 which terminates in a forked end 89, straddling the operating rod 88 inwardly of the fixed abutment 86 integral with the rod 88. The lever 82 is alsoprovided with an integral ring portion 9| for the reception of a hook stick operating member or.

with'the release tube 92, tomove it to the dotted with the end wall of the upper terminal cap 22.

This removes the enlarged head portion 84 of the release tube 92 from supporting relation with respect to head 88 of the actuating rod 88, and permits the rod 88 to move inwardly beneath shoulder 98 on the head 94, under the influence of the compression spring 98. This obviously will move the latch release lever in a clockwise direction about its .pivot 83 and move the latch 28 to the dotted line position shown in Fig. 6, to thereby release the upper end of the fuse from the latch and permit the fuse to move outwardly and downwardly to a drop-out position as before. It should be noted that in this embodiment of my invention the. latch releasing means is independent of the force exerted by the spring 68, which may be very slight adjacent the end of its path of movement. The, only function of the spring 68 in releasing the latch 28, is to remove the'enlarged head portion 94 of the release sleeve 92 from supporting relation with respect to the head 88 of the actuating rod 88. The latch releasing means including the lever 82, actuating rod 88, spring 98, and the enlarged head 94 of the tube 92, may be considered as in a cooked condition, and the tube 92 acts in a trigger fashion line position-shown in Fig. 6 into engagement 5 to release the latch releasing spring 98 which moves the lever 82 to release the latch 28.

The fuse I6, in the embodiment of my invention shown in Fig. 6, may also be manually moved into and out of engagement with its cooperating circuit contacts. Thus, if it is desired to manually move the fuse out of engagement with its line contacts from the position shown in Fig. 6, a hook stick or other operating member may be inserted in the aperture in ring 9| of the latch release lever 82, to exert a downward and outward pull on the latch to rotate the same about its pivot 83 to the dotted line position shown in Fig. 6, to release the latch 28 and permit the fuse to be manually moved out of the circuit. The fuse may be manually reinserted in the dircuit, obviously, by moving the hook stick in the opposite direction. In the manual closing of the fuse 16 in this form of my invention, the operating lever 82 has an added function. When the fuse is blown and a refill is inserted in place of the blown refill unit in the manner described in the aforementioned Rawlins patent, the release tube 82, being freely slidably mounted within the fuse tube 48 may not be finally D sitioned in the position shown in full lines in Fig. 6, especially if the fuse is refilled in inverted position. However, this is immaterial since, when the fuse is manually moved in a counterclockwise direction about its lower pivot into engagement with the line contacts, by means of a hook stick inserted in the aperture in ring 8| of the latch release lever 82, such movement will cause counterclockwise rotation of the latch release member 82 about its pivot 88,-thereby causing the forked end 89 of the latch releaselever to exert an outward pull on the actuating rod 88 to thereby withdraw the actuating rod and allow the releas tube 92 to fall downwardly in the fuse tube under the influence of gravity to a position where the shoulder 96 engages with the head 88 on "the inner end of the actuating rod 88. It can thus be seen that in the event that the re.- lease tube 92 is improperly positioned when the fuse is assembled, it will automatically assume contacts.

leased by the spring which elongates or drawsout the arc formed upon fusion of the fusible element; and in the second form, this same spring acts in a trigger-like fashion to release alatch spring which does the work of releasing the fuse from the latch which maintains it in its associated circuit.

Having described preferred embodiments of.

my invention in accordance with the patent statutes, I wish it to be understood that my invention is not limited to the particular embodisaid latch release means in response tofusing of said fusible means.

minal in engagement with said contact, conducting means in said tube including a fusible means connected to said terminal, resilient means engaging said conducting means and normally maintained in stressed condition by said fusible ments disclosed herein, since it will be obvious v to persons skilled in the art that many changes and modifications may be made in these particular structures without departing from the broad spirit and scope of my invention. Therefore, I desire that my invention be interpreted as broadly as possible and that it be limited only by what is expressly set forth in the following claims.

I claim as my invention:

1. In a circuit interrupter, means for automatically interrupting a circuitin response to the passage of currents therethrough greater than a predetermined magnitude, an enclosure therefor, means movably mounted on said enclosure and having a part projecting through a side wall of said enclosure, so as to be operated in response to a circuit interrupting operation 'of said interrupting means.

a .pair of terminals, means in said tube including a fusible element connecting said terminals, and a release member movably mounted on said tube and having an operating part projecting through the side of said tube so as to be operated in response to blowing of said fusible element.

4. In a circuit interrupter, means for automatically interrupting a circuit in response to the passage of currents therethrough greater than a predetermined magnitude, spring means normally maintained in a stressed condition by said interrupting means but adapted to be released upon operation of said interrupting means to interrupt the circuit, means including an unlocking member pivotally carried by said inter= rupter and an operating part coupled for movemeans, whereby upon fusion of said fusible means said resilient means is operable to move a portion of said conducting means to elongate the are formed, and means positioned to be positively err-'- gaged by said portion of said conducting means after predetermined movement thereof to release said locking means.

7. In a circuit interrupter, a fuse tube having a terminal adjacent one end thereof, a contact, said tube being movably mounted so that said terminal may move with the tube into and out of engagement with respect to said contact, locking means for maintaining said fuse tube terminal in engagement with said contact, conducting means including a fusible means in said tube and connected to said terminal, resilient means engaging said conducting means and normally maintained in stressed condition by said fusible means, whereby upon fusion of said fusible means said resilient means is operable to move a portion of maintaining said last-mentioned means in a lock.

' releasing position.

8. In a circuit interrupting device, a tubular in- 'terrupter casing having terminals adjacent opment with said member and positioned in the .path of movement of a portion of said spring means when released, whereby said unlocking member is actuated in response to an interrupting operation of said interrupting means.

5. In a circuit interrupting device, a pair of spaced contacts, a fuse tube having spaced terminals, latch means for maintaining said terminals in engagement with said contacts, latch release means movably mounted on said tube and including an operating part extending into said tube through a side wall thereof, means within said tube connecting said terminals and including fusible means, said connecting means embodying a part adapted to actuate the operating part of posite ends thereof, conducting means in said casing and connecting said terminals and including fusible means connected to an arc drawing terminal, resilient means normally held in a stressed condition by said fusible means and operable upon melting of said fusible means to move said are drawing terminal away from said fusible means to elongate the resulting arc, said resilient means and are drawing terminal constituting a movable assembly, and means engageable by said assembly at a point in the path of movement thereof prior to the point where the stress of said resilient means is entirely relieved, for actuating latch releasing-means on said casing only after predetermined arc elongation, and for maintaining said last-mentioned means in a lock releasing position.

9. In a circuit interrupting device, a tubular interrupter casing having terminals adjacent opposite ends thereof, conducting means in said casing and connecting said terminals and including fusible means connected to an are drawing terminal, resilient means normally held in a stressed condition by said fusible means and operable upon melting of said fusible means to move said arc drawing terminal away from said fusible means to elongate the resulting arc, said resilient means and arc drawing terminal constituting a movable assembly, actuating means slidably mounted in said casing and engageable by said assembly at a point in advance of the end of its path of movement, and latch releasing means movably mounted on said casing and having a part extending through a wall ofsaid casing into engagement with said actuating means to be actuated thereby.

10. In a circuit interrupting device, a tubular interrupter casing having terminals adjacent opposite ends thereof, conducting means in said casing and connecting said terminals and including fusible means connected to an are drawing terminal, resilient means normally held in a stressed condition by said fusible means and operable upon melting of said fusible means to move said are drawing terminal away from said fusible means to elongate the resulting arc, said resilient means and are drawing terminal constituting a movable assembly, actuating means arc drawing terminal away from said fusible means to elongate the resulting are, said resilient means and are drawing terminal constituting a movable assembly, means of a material capable of evolving an arc extinguishing gas when in proximity to an electric are forming a passage for said arc drawing terminal, and means engageable by said assembly when said are drawing terminal reaches a position adjacent the end of said passage but in advance of the end of its movement under the influence of said resilient means for slidably mounted in said casing and engageable by said assembly at a point in advance of the end of its path of movement, and latch releasing means movably mounted on said casing and having a part extending through a wall of said casing into engagement with said actuating means, means normally biasing said latch releasing means to releasing position, said latch releasing means being maintained in an inactive position by engagement of said part with said actuating means. r

11. In a circuit interrupting device, a tubular interrupter casing having terminals adjacent opposite ends thereof, conducting means in said casing connecting said terminals and including fusible means connected to an are drawing terminal, resilient means normally held in a stressed condition by said fusible means and operable upon melting of said fusible means to move said are drawing terminal away from said fusible means to elongate the resulting arc, said resilient means and are drawing terminal constituting a movable assembly, latch releasing means on said casing adapted for movementv relative to said casing but normally restrained by trigger latch means positioned to be-released by said movable assembly after'predetermined movement thereof. v

12. In a circuit interrupting device, a tubular interrupter casing having terminals adjacent opposite ends thereof, conducting means in said casing connecting said terminals and including means for automatically interrupting the circuit in response to the passage therethrough of ourrents greater than a predetermined value, a spring assembly normally maintained in a stressed condition by said interrupting means and operable following an interrupting operation to draw out the resulting arc, a contact, means movably supporting said casing adjacent one end thereof, and latch means engageable with said casing adjacent the other end thereof'for maintaining one of said latch means, trigger latch means normally restraining said latch releasing means, and posiinterrupter casing having terminals adjacent opposite ends thereof, conducting means in said casing connecting said terminals and including fusible means connected to an are drawing terminal, resilient means normally held in a stressed condition by said fusible means and operable upon melting of said fusible means to move said actuating latch releasing means on said casing.

14. In a circuit interrupter, a tubular interrupter casing, latch releasemeans for said casing including a bell crank mounted on said casing and having one leg thereof extending through a wall of said casing, and interrupting meansin said casing for actuating said latch release means following an interrupting operation.

15. In a circuit interrupter, a tubular interrupter casing, latch releasev means movably mounted on said casing, means including a part extending into said casing for normally biasing said latch release means for movement relative to said casing, trigger means for normally preventing such movement, and interrupting means in said casing adapted to trip said trigger means in response to an interrupting operation.v

16. A flanged end closure for aninterrupter casing and having a latch engaging part, latch release means movably mounted on said closure and including an actuating part extending through an opening in said flange.

17. A flanged end closure for an interrupter 4 casing having a latch engaging projection, latch release means movably mounted on said closure and including a transversely slidable actuating part extending through an opening in said flange.

in response to the passage therethrough of currents greaterthan a predetermined value, a spring assembly normally maintained in a stressed condition by said interrupting means and operable following an interrupting operation to draw out the resulting are, a contact means movably supporting said casing adjacent one end thereof, latch means engageable with said casing adjacent the other end thereof for maintaining at least one of said terminals in engagement with said contact, said casing-being biased for movement of said one terminal away from said contact, and latch release means including a part engageable by said spring assembly intermediate the ends of its arc drawing movement to release said latch.

' 19. In a circuit interrupter, a tubular interrupter casing, latch release means movably mounted on said casing, means including a part extending into said casing for normally biasing said latch release means for movement relative to said casing, trigger latch means for normally preventing such movement, circuit interrupting means in said casing adapted to release said trigger latch means in response to an interrupting operation, said latch release'means including a manually operable latch releasing part'operable' in one direction for latching said trigger latch' means, and in another direction for performing a latch releasing operation without disturbing said trigger latch means.

20. In a fuse device, a fuse tube having terminals adjacent opposite ends thereof, conducting means connecting said terminals including a fusible means in said tube, stressed resilient means connected between one terminal of said fusible means and a part fixed with respect tosaid tube to move 'said terminal upon fusion of said fusible means in a direction to elongate the are formed, and latch. release means movably mounted on said tube and including a part projecting into said tube normally spaced from said terminal of said fusible means but in the path of movement thereof so as to be actuated thereby a predetermined time after fusion of said fusible means.

21. In a circuit interrupting device, a tubular interrupter casing having terminals adjacent opr posite ends thereof, conducting means in said casing and connecting said terminals and including fusible means connected to an are drawing terminal, resilient means normally held in a stressed condition by said fusible means and operable uponmelting of said fusible means to move said are drawing terminal away from said fusible means to elongate the resulting are, said resilient means and arc drawing terminal constituting a movable assembly, an actuating sl'eeve slidably mounted in said casing and engageable by said assembly at a point in advance of the end of its path of movement, and latch releasing means movably mounted on said casing and having a part extending through a wall of said easing into engagement withsaid actuating sleeve to be actuated thereby.

2291s a circuit interrupting device, a tubular interrupter casing having terminals adjacent opposite ends thereof, conducting means in said casing and connecting said terminals and including fusible means connected to an are drawing slidably mounted in said casing and engageable by said assembly at a point in .advance of the end of "its path of movement, latch releasing means movably mounted on said casing and having a part extending through a wall of said easing into engagement with said act vating means, means normally biasing said latch releasing means to releasingposition, said latch releasing means being maintained in an inactive position by engagement of said part with an abutment on said actuating means, whereby upon melting of said move said biasing part for engagement by said trigger latch means, and in another direction for performing a latch releasing operation without disturbing said trigger latch means.

24. In a circuit interrupting device, a tubular interrupter casing having terminals adjacent opposite ends thereof, spaced contacts, -means mounting said casing for. movement ofat least one of its terminals into and out of engagement the resulting are, said resilient means and are drawing terminal constituting a movable assembly, means of a material capable of evolving an arc extinguishing gas'when in proximity to an electric are forming a passage for said are drawing terminal, and means engageable by said assembly when said are drawing terminal reaches a position adjacent the end of said passage but in advance of the end of its movement under the influence of said resilient means for releasing said latch means. i

25. In a fuse device, a fuse tube having terminals adjacent opposite ends thereof, conducting means connecting said terminals including a fusible means in'said tube, stressed resilient means connected between one terminal of said fusible means and a part fixed with respect to said tube to move said terminal upon fusion of said fusible means in a direction to elongate the are formed,

latch release means movably mounted on said tube and including a part projecting into said tube normally spaced from said terminal of said fusible means but in the path of movement thereof so as to be actuated thereby a predetermined time after fusion of said fusible means, and manually operable means for actuating said latch release means.

I 26. In a circuit interruptingdevice, a tubular interrupter casing having terminals adjacent opposite ends thereof; conducting -means in said casingconnecting saidterminals and including fusible means connected to an are drawing terminal, resilient means normally held in a stressed condition by said fusible means and operable upon melting of said fusible means to move said arc, drawing terminal away from said fusible means to elongate the resulting arc, said resilient fusible means said resilient means is operative to elongate the arc and; engage said actuating means to move said abutment from engagement with-said releasing means part, and permit said biasing means to actuate said latch releasing means.

23. In a circuit interrupter, a tubular interrupter casing, latch release means. movably mounted on said casing, means including a part extending into said casing for normally biasing saidlatch release means for-movement relative to said casing, trigger latch means for normally preventing such movement, circuit interrupting means in said casing adapted'to release said trigger latch means in response to an interrupting operation, said latch'release means also including a manually operable latch releasing lever having a lost motion connection with said biasing part, whereby said lever is operable in one direction to means and are drawing-terminal constituting a movable assembly,.latch engaging means mounted for movement relative to said casing, restraining means movably mounted on said casing for restraining movement of said latch engaging means, said restraining means having an actuating part positioned in the path of movement of said movable assembly so as to be moved thereby upon fusion of said fusible means to a non-restraining position.

. 27. In a circuit interrupting device, a tubular interrupter casing having terminals adjacent opposite ends thereof, conducting means in said casing connecting said terminals and including fusible means connected to an are drawing ter'-- minal, resilient means normally held in a stressed condition by said 'fusible means and operable upon melting of said fusible means to move said are drawing terminal away from said fusible means and are drawing terminal constituting a movable assembly, latch engaging means mounted for movement relative to said casing, restraining means movably mounted on said casing and normally biased to a position for restraining movement oi said latch engaging means. said restraining means having an actuating part positioned in the path or movement of said movable assembly so as to be moved thereby upon iusion oi said fusible means to a non-restraining position.

28. In a circuit interrupting device, a tubular interrupter casing having terminals adjacent opposite ends thereoi,- spaced contacts, means mounting said casing for movement oi at least one of its terminals into and out oi engagement with at least one of said contacts, latch means ior maintaining said casing in a position wherein its terminals are in engagement with said contacts, conducting means in said casing connectin: said terminals and including fusible means connected to an arc drawing terminal, resilient means normally held in a stressed condition by said fusible means and operable upon melting oi said fusible means to move said are drawing terminal away from said fusible means to elongate the resulting arc, said resilient means and arc drawing terminal constituting a movable assembly, means of a material capable oi evolving'an arc extinguishing gas when in proximity to an electric arc forming a passage for said are drawin: terminal, and means engageable by said assembfy when said arc drawing terminal reaches a position in its path of movement adjacent the end or said passage but prior to the point where the stress or said resilient meansis entirely relieved ior releasing said latch means to permit said casing to disengage at least said one terminal thereof from said one contact.

JAMES M. WALLACE. 

